Apparatus for measuring limited flow capacities

ABSTRACT

The present disclosure is directed to an apparatus for measuring limited flow capacities, particularly for monitoring continuouscycle automatic dispensing and analyzing devices. The apparatus comprises a measuring chamber adapted to be charged with a liquid to be measured, inlet means for introducing a quantity of liquid into the lower portion of the measuring chamber, a siphon tube communicating with the measuring chamber at substantially the same level as the inlet means, a first and second level sensor device disposed in the lower portion and upper portion of the measuring chamber respectively, said level sensor devices generating electrical signals when a predetermined level is passed and at least one clock means associated with the sensor devices for determining at least one filling time.

United States Patent Ern [54] APPARATUS FOR MEASURING LIMITED FLOWCAPACITIES 51 Feb. 15, 1972 Primary Examiner.lerry W. MyracleAttorneyCraig, Antonelli & Hill [57] ABSTRACT The present disclosure isdirected to an apparatus for measuring limited flow capacities,particularly for monitoring continuous-cycle automatic dispensing andanalyzing devices. The apparatus comprises a measuring chamber adaptedto be charged with a liquid to be measured, inlet means for introducinga quantity of liquid into the lower portion of the measuring chamber, asiphon tube communicating with the measuring chamber at substantiallythe same level as the inlet means, a first and second level sensordevice disposed in the lower portion and upper portion of the measuringchamber respectively, said level sensor devices generating electricalsignals when a predetermined level is passed and at least one clockmeans associated with the sensor devices for determining at least onefilling time.

12 Claims, 2 Drawing Figures APPARATUS FOR MEASURING LIMITED FLOWCAPACITIES BACKGROUND OF THE INVENTION The present invention is directedto an apparatus for measuring limited flow capacities, particularly formonitoring continuous-cycle automatic dispensing and analyzing devices.

If continuous-cycle automatic dispensing and analyzing devices are tofunction properly, the exact quantities of liquid being handled must beknown. It is also desirable to monitor the dispensing and deliveryelements for correct operation so that any faults occurring can bedetected and eliminated.

Depending upon the particular problem to be solved, only limited flowcapacities have to be monitored so that not all the conventionalvolumeters are suitable. There are many methods of measuring flowcapacities for example, volumetric processes, restricted-flow processes,float-regulated processes and processes using inductive primaryelements. Suitable for limited flow capacities, are drum counters (up to3 liters/hour), and suspended-particle meters (up to 0.5 liters/hour).Only the drum counter has the additional property of giving measurementsindependent of the density of the liquid.

It will be seen that these known processes are not universallyapplicable and, depending upon the particular problem to be solved, havespecific advantages and disadvantages.

SUMMARY OF THE INVENTION An object of the present invention is toovercome the prior art disadvantages in measuring limited flowcapacities, particularly for monitoring continuous-cycle automaticdispensing and analyzing devices.

Another object of the present invention is to provide an improved aparatus for measuring limited flow capacities which are independent ofthe density of the liquid.

Other objects and further scope of applicability of the presentinvention will become apparent from the detailed description givenhereinafter; it should be understood, however, that the detaileddescription and specific examples, while indicating preferredembodiments of the invention, are given by way of illustration only,since various changes and modifications within the spirit and scope ofthe invention will become apparent to those skilled in the art from thisdetailed description.

Pursuant to the present invention it has been found that theabove-mentioned disadvantages may be eliminated and a much improvedapparatus for measuring limited flow capacities can be provided whichcomprises a measuring chamber adapted to be charged with liquid to bemeasured, a siphon tube opening into the measuring chamber, levelsensors for generating electrical signals when a desired liquid level ispassed, and at least one clock for determining at least one fillingtime.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention will become morefully understood from the detailed description given hereinbelow and theaccompanying drawings which are given by way of illustration only andthus are not limitative of the present invention and wherein,

FIG. 1 diagrammatically illustrates the apparatus according to thepresent invention, and

FIG. 2 illustrates another embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the apparatusof the present invention and particularly to FIG. 1, a measuringcylinder 2 is connected to a pipe 7 carrying a quantity of liquid 1 tobe measured. A siphon pipe 3, which initially extends upwards along themeasuring cylinder 2 for a distance before reversing its direction, isopen at the same level as the pipe 7. The open end of the downwardlyextending portion of the siphon pipe 3 is beneath the level of the inletpipe 7 and discharges the liquid flowing through the pipe 3 into acollecting vessel 8.

A first electrode 4 is mounted in the bottom of the measuring cylinder2. A second electrode 5 projects out of the top of the measuringcylinder. The lower part of the electrode 5 extends beneath the curve orbend in the siphon pipe 3. The electrodes 4 and 5 act as level sensorsand are connected to an electric circuit containing a voltage source 9and a relay [0.

As long as the column of liquid in the measuring cylinder 2 does notreach the electrode 5, the electric circuit is broken and the relay 10remains in a position of rest. When the column of liquid reaches theelectrode 5, current flows through the liquid, which is assumed to beelectrically conductive, thereby activating the relay 10. The relay 10has, for example, one break contact 101 and one make contact 102. Clocks1], 12, are supplied with voltage through these contacts. The clock 11is connected to the make contact 102 and works only when the relay 10 isactivated. The clock 12 is connected to the break contact 101 and isstopped while the relay 10 is activated. These clocks are provided withdevices 110, Ill and 120, 121 for setting advance times with which idealtimes can be set. If the running time of one of the clocks exceeds thisset ideal time from a given starting point, an appropriate contactdevice generates a signal indicating deviation of the time intervalprovided for completion of the operation.

In the present situation the volume measurement takes place as follows:

The quantity of liquid 1 to be measured charges the measuring cylinderfrom an initial level 20. When the column of liquid reaches the level21, the zone between the electrodes 4 and 5 becomes conductive, therelay I0 is activated and the clock 11 which has been wound back to zerobeforehand begins to measure the time. The measuring cylinder continuesto be charged until the upper bend in the siphon tube 3 communicatingwith it has been reached, after which the measuring cylinder isautomatically emptied by the siphon pipe 3.

As a result, the liquid level falls from point 22 because the quantityremoved per unit of time is greater than the quantity being supplied.When the level falls below point 21, the circuit for the relay 10 isbroken and the clock 11 stops. In its place, the clock 12 is started,having hitherto remained in its starting position. The liquid levelcontinues to fall until it reaches the level 20 of the socket for thesiphon pipe 3, which signifies that the emptying procedure is over andthat the measuring cylinder 2 can again be filled. When level 21 isagain reached, the relay 10 is reactivated which stops clock 12 andstarts clock 11 again. Thus, throughout the entire charging and emptyingcycle one of the clocks 11 or 12 is working and the point of time atwhich one clock stops and the other clock starts can be used as thecriteria for the correct filling time. As already mentioned, comparisonwith a predeterminable ideal time is initiated to this end.

If the filling time differs from this ideal time, and particularly if itis longer, this means that either the feed capacity is too small orthere is a leak in the pipe through which some of the liquid beingdelivered is escaping. The signal thus released indicates that theinstallation should be inspected.

If the filling and emptying cycles are to be determined with a highdegree of accuracy, it is advantageous to provide an electrode 6 in themeasuring cylinder above the inflow level 20 in place of the lowerelectrode 4. The lower liquid level 20 where emptying of the measuringcylinder stops and filling begins, is not precisely defined because itis governed by the diameter of the inlet delivery pipe 7 and siphon pipe3. However, the electrode 6 produces a defined level 23 at which therelay circuit is made or broken.

It would also be quite possible to use contact-free level sensorsinstead of the electrodes 4, 5 and 6, 5 dipping into the liquid. Anexample of this is shown in FIG. 2.

Photoelectric devices 30 and 31 are used instead of the electrodes. Whenthe liquid level passes these devices they initiate the switchingfunctions necessary for actuating the relay 10.

Since in this apparatus volume measurement is converted into a timemeasurement, a high degree of accuracy is obtained. lf. for example, onemeasurement is made per minute, errors can be reduced to less than 10.5percent. If several measurements are collected over prolonged periods,the possibility of error is even further reduced.

The apparatus according to the present invention is of particularadvantage in cases where small quantities (0.5 liter/hour) have to bemeasured. in addition, the measurements are not governed by the densityof the liquid.

The invention being thus described, it will be obvious that the same maybe varied in many ways. Such variations are not to be regarded as adeparture from the spirit and scope of the invention, and all suchmodifications as would be apparent to one skilled in the art areintended to be included.

What is claimed is:

1. An apparatus for measuring limited flow capacities which comprises ameasuring chamber adapted to be charged with a liquid to be measured,inlet means for introducing a quantity of liquid into the lower portionof the measuring chamber, a siphon tube communicating with the measuringchamber at substantially the same level as the inlet means, a first anda second level sensor device disposed in the lower portion and upperportion of the measuring chamber respectively, said level sensor devicesgenerating electrical signals when a predetermined level is passed andfirst and second clock means connected to the sensor devices fordetermining a first and a second filling time, said first and secondlevel sensor devices forming part of electric circuit means forcontrolling said first and second clock means, said electric circuitmeans including first means for actuating said first clock means as longas the liquid level is in the range of said second level sensor deviceand at the desired level and second means for actuating said secondclock means when the liquid level falls below said desired level.

2. The apparatus of claim I, wherein the first and second level sensordevices are first and second electrodes disposed in the measuringchamber.

3. The apparatus of claim 2, wherein the second electrode is arranged atthe desired level to be measured.

4. The apparatus of claim 2, wherein the first electrode is arranged inthe lower portion of the measuring cylinder below the point where thesiphon tube communicates with said cylinder.

5. The apparatus of claim 2 wherein the first electrode is arranged inthe lower portion of the measuring cylinder above the point where thesiphon tube communicates with said cylinder.

6. The apparatus of claim 2, wherein the siphon tube extends upwardsalong the measuring cylinder from the bottom portion to the top portionthereof and then reverses its direction extending downward until itterminates below the level ofthe inlet means.

7. The apparatus of claim 6, wherein the second electrode is effectivein a level range determined by the reversing bend portion of the siphontube.

8. The apparatus of claim 6, wherein the lower portion of the secondelectrode extends beneath the reversing portion of the siphon tube andthe upper portion extends out of the measuring cylinder.

9. The apparatus of claim 1, wherein the level sensors are photoelectricdevices.

10. The apparatus of claim 1, wherein said first and second clock meansare provided with setting means for ideal times and signal means whichrespond to deviations of the measuring time from the ideal time.

11. The apparatus of claim 1, wherein the discharge end of the siphontube communicates with a collecting vessel.

12. The apparatus of claim 1, wherein the level sensors are connected toan electrical circuit containing a voltage source and a relay device.

1. An apparatus for measuring limited flow capacities which comprises ameasuring chamber adapted to be charged with a liquid to be measured,inlet means for introducing a quantity of liquid into the lower portionof the measuring chamber, a siphon tube communicating with the measuringchamber at substantially the same level as the inlet means, a first anda second level sensor device disposed in the lower portion and upperportion of the measuring chamber respectively, said level sensor devicesgenerating electrical signals when a predetermined level is passed andfirst and second clock means connected to the sensor devices fordetermining a first and a second filling time, said first and secondlevel sensor devices forming part of electric circuit means forcontrolling said first and second clock means, said electric circuitmeans including first means for actuating said first clock means as longas the liquid level is in the range of said second level sensor deviceand at the desired level and second means for actuating said secondclock means when the liquid level falls below said desired level.
 2. Theapparatus of claim 1, wherein the first and second level sensor devicesare first and second electrodes disposed in the measuring chamber. 3.The apparatus of claim 2, wherein the second electrode is arranged atthe desired level to be measured.
 4. The apparatus of claim 2, whereinthe first electrode is arranged in the lower portion of the measuringcylinder below the point where the siphon tube communicates with saidcylinder.
 5. The apparatus of claim 2 wherein the first electrode isarranged in the lower portion of the measuring cylinder above the pointwhere the siphon tube communicates with said cylinder.
 6. The apparatusof claim 2, wherein the siphon tube extends upwards along the measuringcyliNder from the bottom portion to the top portion thereof and thenreverses its direction extending downward until it terminates below thelevel of the inlet means.
 7. The apparatus of claim 6, wherein thesecond electrode is effective in a level range determined by thereversing bend portion of the siphon tube.
 8. The apparatus of claim 6,wherein the lower portion of the second electrode extends beneath thereversing portion of the siphon tube and the upper portion extends outof the measuring cylinder.
 9. The apparatus of claim 1, wherein thelevel sensors are photoelectric devices.
 10. The apparatus of claim 1,wherein said first and second clock means are provided with settingmeans for ideal times and signal means which respond to deviations ofthe measuring time from the ideal time.
 11. The apparatus of claim 1,wherein the discharge end of the siphon tube communicates with acollecting vessel.
 12. The apparatus of claim 1, wherein the levelsensors are connected to an electrical circuit containing a voltagesource and a relay device.